Electric tool



Feb. 19, 1929. l,702 ;742

W. MORETTI ELECTRIC TOOL Filed June 10, 1925 I 2 Sheets-Sheet 2 vflazlay) ORNEY INVENTOR BY 971d? 7% ATI' Patented Feb. '19, 1929.

WHITFIELD MORETTI, F MONTAGUE, MASSACHUSETTS, ASSIGNOR TO KILLERS FALLS COMPANY, OF MILLERS FALLS, MASSACHUSETTS, A CORPORATION OF MASSACHU- SETTS.

ELECTRIC TOOL,

Application filed June 10, 1925. Serial No. 36,142.

This invention relates to an improved type of portable electric tool.

It is an object to provide a device of this type which will efficiently perform the purposes for which it is intended, and which will also be economically and readily manufactured and easily assembled. It is a further object to construct an elec trio tool which will operate at maximum efiiciency over long periods of time, and the parts of which will be maintained at a satisfactory temperature during the entire period of operation.

A still further object resides in providing an electric tool the operating mechanism of which will be effectually housed, but in which those parts which should be inspected, renewed or adjusted at comparatively frequent intervals will be readily accessible.

Another object is that of furnishing an electric tool capable of use in numerous different connections, particularly intended to be .employed as a drill and which will be compact in construction and light in weight so that it may readily be manipulated by an operator, and in which, furthermore, the control will be arranged with respect to the other mechanism thereof so that the tool may be handled with nicet and the finished work will accordingly be ree from marring and other errors.

With these and further objects in mind, the invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will beexemplified in the construction hereinafter set forth, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is a plan view of one form of tool embodying the improved construction of the present invention;

Fig. 2 is an end view thereof, and showing one side of the casing detached;

Fig. 3 is a side elevation of the device as shown in the preceding fi ures;

Fig. 4 is an enlarged sectional side view thereof;

Fig. 5 is a transverse sectional view taken along the lines 55 and in the direction of the arrows of Fig. 4;

Fig. 6 is an enlarged fragmentary sectional side view of the trigger and switch mechanism; and

Fig. 7 is a face view of the trigger.

In the present embodiment the invention has been shown as a drill which includes a casing having a main body 10, to the for-- ward end of which a gear and spindle head 11 is detachably secured, as, for example, by the use of screws 12. The-rear end of the casing is extended to provide-an integral head 13 and a handle 14, the latter being in the nature of what is commonly known as a pistol-grip and extending substantially in line with the main body of the casing. This handle is hollow and s fittedwith a detachable plate 15 so that its interior may be exposed, the plate being extended to provide a head-portion 16 complementary to the head 13.

Situated within the interior of the casmg and locked relatively thereto is the field 17 of a motor, and an armature 18 is mounted upon a shaft'l9, the outer end of which is carried by a bearing 20 housed within a suitable recess formed in the head 11. The inner end of the armature shaft is also carried by a suitable'bearing 21, and this bearing ma be supported by the head 13 by forming t e latter with an inwardlyextending collar 22 of ample inner diameter to accommodate both the bearing and a packing member 23, which latter serves to prevent the escape of lubricant from within the chamber provided by the collar. In order to renew the lubricant within this chamber without the necessity of opening up the casing, the latter may be provided with a port communicating with the chamber, the outer end thereof being preferably controlled by a ball-valve 24. It will furthermore be apparent in the present instance that the motor brushes 25 are mounted so that their bodies extend into openings formed in the handle-portion 14, it being appreciated that screw-caps 26 may be employed to retain them in position.

In order to control the motor an electric conduit 27 may enter the casing through an opening in the base of the handle-portion 14, and this conduit may be reenforced against acute bending, and also be prevented from relative movement at its point of entry to the casing, by utilizing a tube 28 of resilient material enclosing the conduit at this point and for a short distance beyond the handle, and employing a clamping-member 29 in association with the casing and bearing against this tube. The inner edge of that portion of the handle 14 which extends at substantially right-angles to the body of the casing is formed with an opening or slot 30 at its upper end, and

extending through and beyond this opening is a trigger-member, which may embrace a shank 31 substantially U-shaped in cross section in order to rigidity the same. The upper end of this shank, as in Fig. 6, may terminate in a hook 32 hearing against a trigger stop member 33, the trigger being rockingly supported by bearing against the upper edge of the switch casing 34 at a point adjacent the juncture of its hook and shank, and its inner face being engaged by a switch-moving member 35 so as to normally retain it in the position illustrated in the several views.

The switch assembly will not be described in detail, but one of the leads of the cable 27, in the present instance, is connected directly with one of the brushes 25 of the motor, while the second lead'is arranged in series with this switch and connected with the second motor brush.

With reference to the head 11 it will be observed that the same has an interior contour best adapted for the accommodation of the outer end of the armature shaft 19, the spindle or chuckshaft 36 and a countershaft 37. Secured. to the first of these shafts is a gear 38 meshing with a comparatively large gear 39 secured to the countershaft 37,-this shaft also mounting a comparatively small gear '40, in turn meshing The interior of the head 11 is preferably packed with lubricant, and in order to prevent the escape of the latter it will be observed that in the present instance a plate 45 is interposed between the outer edge of the main casing body-10 and a shoulder formed adjacent the inner edge of the head. This plate has an opening of ample size to accommodate the armature shaft 19, and obviously serves to prevent the rearward flow of lubricant into the main casing body. To also prevent the rearward flow of this lubricant through the opening furnished for the armature shaft and parts assembled therewith, the latter may carry a disk 46, which is fixedly secured thereto at a point adjacent the rear face of the gearBS and the forward face of the plate 45 so that the likelihood of the lubricant being forced into the main casing is reduced to a minimum.

In the present instance, in order to cool the motor mechanism a fan 47 may be coupled to the shaft 19 at a point immediately adjacent the rear face of the plate 45, and the casing 10 at this point is formed with a radial series of openings 48 through which the air may be exhausted. In order that the air flow may be most efiectual the fan or impeller 47 is mounted within a chamber, one wall of which is formed by the plate 45', and the second wall of which, in the present instance, is formed by a washer 49 which bears against an annular shoulder formed in the inner face of the casing 10 and is retained in this position by means of springs 50 carried by pins 50, which are associated with the plate 45 and of a sufiicient resiliency to accomplish the result desired. The head 13, together with the complementary portion 16, is formed with openings 51, through which the air is drawn into the casing 10 so that the cool air will lay directly upon the commutator and brus es, and thus, a flow of air may be established with the motor in operation.

It will be appreciated that in use an operator may simply associate a suitable tool with the chuck or other holding device which is attached to the outer end of the shaft 36, and may thereupon, bring the tool to a oint adjacent the work to be erforme lVhile bringing the drill into proper position the same may be grasped, if desired, merel by the handle, and when the motor is to e started this may be ac- 'complished simply by pressing the trigger. Due to the. fact that the handle is' situated latter, and particularly due to the disposition of the same, this will not resultin the tool being thrown out of linewith the work. Furthermore, incident to the-fact that the tool-shaft, i. e., the shaft 36, is preferably not in line with the axial center of the casing, but is rather adjacent the upper edge of the same, the drill-bit or other tool may be accurately sighted with the work.

While working the motor will remain at highest operating elficiency, due to the fact that its temperature is constantly main-' tained at a substantially normal degree by virtue of the fan, which, particularly due to the fact that it is virtually enclosed within a compartment, serves to draw a maximum amount of cooling air past the operating parts and to discharge the heated air through the openings 48.

The leads extending beyond the switch and towards the motor brushes, being enclosed within the conduit provided in the lower portion of the handle, are eiiectually housed against damage. At this time it is also to be noted that, due to the manner in which the cable 27 is reentorced by the tube 28, the former cannot be subjected to such an acute strain as will be likel to result in its becoming broken. Also, incident to the fact that the tube, and, hence, the cable, is locked'in place, no strain will be thrown upon the wires and their connections.

Finally, it will be appreciated that the washer 49, as aforestated, will be maintained in position, incident to the provision of the shoulderwithin the casing and the springs which urge it into contact with this'shoulder when the parts are in their normal assembled positi 011$.

At any time it becomes necessary it will be obvious that the switch and brush assembly may be inspected and adjusted by simply removing the cover plate 15, together with the extension 16 thereof, and it is obvious that the brushes 25 may be completely withdrawn if this is'desirable. Incident to the reduction drive utilized any starting torque may be overcome even if the -may be rendered accessible by simply grasping the armature; and moving the head away from the same. By this expedient the plate 45 which is retained against other than 1'0 tative movement relatively to the shaft 19 will uncover the gear train, it being observed above construction, and different embodiments of the invention could be made, without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. i

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which as a matter of language might be said to fall therebet-ween.

Having described my invention, what I claim as new and desire to secure by Letters lead, the connection between said handle closing an open side of said handle and connecting portion, said plate being provided with a part complementary to a portion of said casing, said part lying at a point adja;

cent said brush assembly. t

4. An electrictool, includmg, 1n combination, a casing, heads at opposite ends of the same, anti-friction bearings associated with said heads, an armature shaft detachably associated with said bearings, a motordriven toolshaft, a plurality of gears within one of said heads and connecting said lastnamed shaft with said armature shaft, a

plate segregating said gears from said motor, and adisk associated w1th said armatare shaft and arranged ad acent said plate.

5.- A tool, including a casing formed with intake and outlet openings, a shaft rotatable within said casing, a fan secured to said shaft and in line with said outlet 0 enings, an imperforate plate beside said an and extending beyond said outlet openings through which said shaft passes, a ring shaped plate extending inwardly from said casing and positioned between the fan and intake openings, said plates providing a compartment for said fan, a gear casing beyond said first-named plate, said shaft extending into said casing, and a disk connected with said shaft Within said latter casing and adjacent the said first-named plate 6. A tool, including a casing formed with intake and out-let openings, a shaft rotatable within said casing, a fan secured to said shaft and in line with said outlet openings, an imperforate plate held by said casing in a position adjacent said fan, said plate extending beyond said outlet openings and having an opening through which said shaft passes, a ring-shaped plate positioned on the side of said fan opposite said impel-forate plate and held against a shoulder in said casing by means mounted on said imperforate plate, said plates providing a compartment for said fan, a gear casing beyond said first-named plate, said shaft extending into said casing, and a disc connected with said shaft within said latter casing and adjacent the said shaft opening in the said first-named plate whereby leakage is prevented from said gear easing into said fan compartment.

7 A tool, including a casing formed with intake and outlet openings, a shaft rotatable within said casing, a fan secured to said shaft and in line with said outlet openings, an imperforate plate held by said. casing in a position adjacent said fan, said plate extending beyond said outlet openings and having an opening through which said shaft passes, a ring-shaped plate positioned on the side of said fan opposite to said imperforate plateand resiliently held against a shoulder in said casing by means of expansion springs acting against said imperforate plate, said plates providing a compartment for said fan, a gear casing beyond said firstnamed plate, said shaft extending into said casing, and a disc connected with said shaft within said latter-easing and adjacent the said shaft opening in the said first-named plate whereby leakage is prevented from said gear easing into said fan compartment. In testimony whereof I aflix my signature.

WHITFIELD MORETTI. 

